package test;

public class ConcatenationNumber {
    public static void main(String[] args) {
        double date = 9;
        double all  = 0;
        for (int i = 0; i < 10; i++) {
            all += date;
            date = date*10+9;
        }
        System.out.println("前十项的和为："+all);
    }
}
